text: # C++ skeleton for Bison
  
  # Copyright (C) 2002-2015 Free Software Foundation, Inc.
  
  # This program is free software: you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation, either version 3 of the License, or
  # (at your option) any later version.
  #
  # This program is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License
  # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  
  m4_pushdef([b4_copyright_years],
             [2002-2015])
  
  # b4_position_define
  # ------------------
  # Define class position.
  m4_define([b4_position_define],
  [[  /// Abstract a position.
    class position
    {
    public:]m4_ifdef([b4_location_constructors], [[
      /// Construct a position.
      explicit position (]b4_percent_define_get([[filename_type]])[* f = YY_NULLPTR,
                         unsigned int l = ]b4_location_initial_line[u,
                         unsigned int c = ]b4_location_initial_column[u)
        : filename (f)
        , line (l)
        , column (c)
      {
      }
  
  ]])[
      /// Initialization.
      void initialize (]b4_percent_define_get([[filename_type]])[* fn = YY_NULLPTR,
                       unsigned int l = ]b4_location_initial_line[u,
                       unsigned int c = ]b4_location_initial_column[u)
      {
        filename = fn;
        line = l;
        column = c;
      }
  
      /** \name Line and Column related manipulators
       ** \{ */
      /// (line related) Advance to the COUNT next lines.
      void lines (int count = 1)
      {
        if (count)
          {
            column = ]b4_location_initial_column[u;
            line = add_ (line, count, ]b4_location_initial_line[);
          }
      }
  
      /// (column related) Advance to the COUNT next columns.
      void columns (int count = 1)
      {
        column = add_ (column, count, ]b4_location_initial_column[);
      }
      /** \} */
  
      /// File name to which this position refers.
      ]b4_percent_define_get([[filename_type]])[* filename;
      /// Current line number.
      unsigned int line;
      /// Current column number.
      unsigned int column;
  
    private:
      /// Compute max(min, lhs+rhs) (provided min <= lhs).
      static unsigned int add_ (unsigned int lhs, int rhs, unsigned int min)
      {
        return (0 < rhs || -static_cast<unsigned int>(rhs) < lhs
                ? rhs + lhs
                : min);
      }
    };
  
    /// Add \a width columns, in place.
    inline position&
    operator+= (position& res, int width)
    {
      res.columns (width);
      return res;
    }
  
    /// Add \a width columns.
    inline position
    operator+ (position res, int width)
    {
      return res += width;
    }
  
    /// Subtract \a width columns, in place.
    inline position&
    operator-= (position& res, int width)
    {
      return res += -width;
    }
  
    /// Subtract \a width columns.
    inline position
    operator- (position res, int width)
    {
      return res -= width;
    }
  ]b4_percent_define_flag_if([[define_location_comparison]], [[
    /// Compare two position objects.
    inline bool
    operator== (const position& pos1, const position& pos2)
    {
      return (pos1.line == pos2.line
              && pos1.column == pos2.column
              && (pos1.filename == pos2.filename
                  || (pos1.filename && pos2.filename
                      && *pos1.filename == *pos2.filename)));
    }
  
    /// Compare two position objects.
    inline bool
    operator!= (const position& pos1, const position& pos2)
    {
      return !(pos1 == pos2);
    }
  ]])[
    /** \brief Intercept output stream redirection.
     ** \param ostr the destination output stream
     ** \param pos a reference to the position to redirect
     */
    template <typename YYChar>
    inline std::basic_ostream<YYChar>&
    operator<< (std::basic_ostream<YYChar>& ostr, const position& pos)
    {
      if (pos.filename)
        ostr << *pos.filename << ':';
      return ostr << pos.line << '.' << pos.column;
    }
  ]])
  
  
  # b4_location_define
  # ------------------
  m4_define([b4_location_define],
  [[  /// Abstract a location.
    class location
    {
    public:
  ]m4_ifdef([b4_location_constructors], [
      /// Construct a location from \a b to \a e.
      location (const position& b, const position& e)
        : begin (b)
        , end (e)
      {
      }
  
      /// Construct a 0-width location in \a p.
      explicit location (const position& p = position ())
        : begin (p)
        , end (p)
      {
      }
  
      /// Construct a 0-width location in \a f, \a l, \a c.
      explicit location (]b4_percent_define_get([[filename_type]])[* f,
                         unsigned int l = ]b4_location_initial_line[u,
                         unsigned int c = ]b4_location_initial_column[u)
        : begin (f, l, c)
        , end (f, l, c)
      {
      }
  
  ])[
      /// Initialization.
      void initialize (]b4_percent_define_get([[filename_type]])[* f = YY_NULLPTR,
                       unsigned int l = ]b4_location_initial_line[u,
                       unsigned int c = ]b4_location_initial_column[u)
      {
        begin.initialize (f, l, c);
        end = begin;
      }
  
      /** \name Line and Column related manipulators
       ** \{ */
    public:
      /// Reset initial location to final location.
      void step ()
      {
        begin = end;
      }
  
      /// Extend the current location to the COUNT next columns.
      void columns (int count = 1)
      {
        end += count;
      }
  
      /// Extend the current location to the COUNT next lines.
      void lines (int count = 1)
      {
        end.lines (count);
      }
      /** \} */
  
  
    public:
      /// Beginning of the located region.
      position begin;
      /// End of the located region.
      position end;
    };
  
    /// Join two locations, in place.
    inline location& operator+= (location& res, const location& end)
    {
      res.end = end.end;
      return res;
    }
  
    /// Join two locations.
    inline location operator+ (location res, const location& end)
    {
      return res += end;
    }
  
    /// Add \a width columns to the end position, in place.
    inline location& operator+= (location& res, int width)
    {
      res.columns (width);
      return res;
    }
  
    /// Add \a width columns to the end position.
    inline location operator+ (location res, int width)
    {
      return res += width;
    }
  
    /// Subtract \a width columns to the end position, in place.
    inline location& operator-= (location& res, int width)
    {
      return res += -width;
    }
  
    /// Subtract \a width columns to the end position.
    inline location operator- (location res, int width)
    {
      return res -= width;
    }
  ]b4_percent_define_flag_if([[define_location_comparison]], [[
    /// Compare two location objects.
    inline bool
    operator== (const location& loc1, const location& loc2)
    {
      return loc1.begin == loc2.begin && loc1.end == loc2.end;
    }
  
    /// Compare two location objects.
    inline bool
    operator!= (const location& loc1, const location& loc2)
    {
      return !(loc1 == loc2);
    }
  ]])[
    /** \brief Intercept output stream redirection.
     ** \param ostr the destination output stream
     ** \param loc a reference to the location to redirect
     **
     ** Avoid duplicate information.
     */
    template <typename YYChar>
    inline std::basic_ostream<YYChar>&
    operator<< (std::basic_ostream<YYChar>& ostr, const location& loc)
    {
      unsigned int end_col = 0 < loc.end.column ? loc.end.column - 1 : 0;
      ostr << loc.begin;
      if (loc.end.filename
          && (!loc.begin.filename
              || *loc.begin.filename != *loc.end.filename))
        ostr << '-' << loc.end.filename << ':' << loc.end.line << '.' << end_col;
      else if (loc.begin.line < loc.end.line)
        ostr << '-' << loc.end.line << '.' << end_col;
      else if (loc.begin.column < end_col)
        ostr << '-' << end_col;
      return ostr;
    }
  ]])
  
  
  b4_defines_if([
  b4_output_begin([b4_dir_prefix[]position.hh])
  b4_copyright([Positions for Bison parsers in C++])[
  
  /**
   ** \file ]b4_dir_prefix[position.hh
   ** Define the ]b4_namespace_ref[::position class.
   */
  
  ]b4_cpp_guard_open([b4_dir_prefix[]position.hh])[
  
  # include <algorithm> // std::max
  # include <iostream>
  # include <string>
  
  ]b4_null_define[
  
  ]b4_namespace_open[
  ]b4_position_define[
  ]b4_namespace_close[
  ]b4_cpp_guard_close([b4_dir_prefix[]position.hh])
  b4_output_end()
  
  
  b4_output_begin([b4_dir_prefix[]location.hh])
  b4_copyright([Locations for Bison parsers in C++])[
  
  /**
   ** \file ]b4_dir_prefix[location.hh
   ** Define the ]b4_namespace_ref[::location class.
   */
  
  ]b4_cpp_guard_open([b4_dir_prefix[]location.hh])[
  
  # include "position.hh"
  
  ]b4_namespace_open[
  ]b4_location_define[
  ]b4_namespace_close[
  ]b4_cpp_guard_close([b4_dir_prefix[]location.hh])
  b4_output_end()
  ])
  
  
  m4_popdef([b4_copyright_years])
  